title: A downregulation of nNOS is associated to dysmotility evoked by lipopolysaccharide in rabbit duodenum.
abstract: Alterations in gastrointestinal motility have been reported in response to endotoxin. The effects of lipopolysaccharide (LPS) on motility have been attributed to several substances, including prostaglandins and nitric oxide. The aim of this study was to investigate the expression and the contribution of NOS and COX enzymes to the local effect of LPS on ACh-evoked contractions in rabbit duodenum. The ACh evoked contractions were inhibited by LPS in longitudinal and circular muscles of duodenum. L-NNA, aminoguanidine, ODQ, indomethacin, and NS-398 but not NPLA antagonized the inhibitory effect of LPS. Western blot analysis showed protein bands of 155, 130, 70 and 72 kDa for nNOS, iNOS, COX-1 and COX-2 respectively in rabbit duodenum. All of these isoforms were expressed constitutively and only the nNOS was reduced in the presence of LPS. Expression of nNOS, iNOS, COX-1 and COX-2 was detected by inmunohistochemistry in the smooth muscle layers and in the neurons of the myenteric ganglia of rabbit duodenum. In conclusion, LPS locally administered reduces the contractility of rabbit duodenum and a downregulation of nNOS is associated to this effect. The iNOS, COX-1 and COX-2 were expressed constitutively but their expression was not modified by LPS.
authors.affiliation: Department of Pharmacology and Physiology, Faculty of Veterinary Medicine, University of Zaragoza, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Grasa
authors.forename: M P
authors.initials: MP
authors.lastname: Arruebo
authors.forename: M A
authors.initials: MA
authors.lastname: Plaza
authors.forename: M D
authors.initials: MD
authors.lastname: Murillo
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D051545:Cyclooxygenase 1 / Q000096:biosynthesis; D051546:Cyclooxygenase 2 / Q000096:biosynthesis; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects; D004386:Duodenum / Q000187:drug effects*; D005769:Gastrointestinal Motility / Q000187:drug effects* / Q000235:genetics*; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D052248:Nitric Oxide Synthase Type I / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis / Q000235:genetics; D011448:Prostaglandin Antagonists / Q000494:pharmacology; D011817:Rabbits
chemical_list: D016861:Cyclooxygenase Inhibitors; D008070:Lipopolysaccharides; D011448:Prostaglandin Antagonists; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D000109:Acetylcholine